/in/foo.cc: In function 'void Dijkstra()':
/in/foo.cc:38:35: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<Edge>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |                 for (int i = 0; i < G[u].size(); i++) {
      |                                 ~~^~~~~~~~~~~~~